Multi-circuit cycle timer and modular construction

ABSTRACT

A modular electromechanical timer is provided for initiating a timing cycle at a preselected time and for terminating said cycle at the end of a predetermined period. The timing module generally includes two rotary timing dials one being a 24 hour timing dial for setting the time at which the timing cycle should be initiated and the other being a 2 hour timing dial for setting the duration of the predetermined period. The timing dials are coupled together by a gear train and are driven by a common drive shaft connected to the two hour dial. Each of said timing dials are provided with actuator means thereon for tripping a spring biased pivot lever into or out of engagement with a switch means which initiates or terminates the desired timing cycle. A plurality of the timing modules of the present invention may be juxtaposed in a modular unit for controlling timing functions in a plurality of output circuits. The respective modules may be readily removed from the unit and are interchangeable in position. Means are provided to prevent any two timing modules from initiating a timing cycle simultaneously.

United States Patent [1 1 [111 3,830,993

Schulze-Berge Aug. 20, 1974 MULTI-CIRCUIT CYCLE TIMER AND MODULAR CONSTRUCTION [57] ABSTRACT [75] Inventor: Karl J. Schulze-Berge, Manitowoc, A modular electromechanical timer is provided for Wis. initiating a timing cycle at a preselected time and for terminating said cycle at the end of a predetermined [73] Asslgnee' Incorporated whlte Plams period. The timing module generally includes two rotary timing dials one being a 24 hour timing dial for [22] Filed: Apr. 4, 1973 setting the time at which the timing cycle should be initiated and the other being a 2 hour timing dial for [21] Appl 347656 setting the duration of the predetermined period. The timing dials are coupled together by a gear train and [52] US. Cl. 200/35 R, 200/38 R, 200/38 DA are driven by a common drive shaft connected to the [51] Int. Cl. H01h 43/10 w h r i l- E oh of id timing dials are provided [58] Field of Search 62/155, 157, 158, 231, w th a tuat r m ans thereon for tripping a spring bi- 62/234; 200/3340, l7, 18, 168 K; 307/141, ased pivot lever into or out of engagement with a 1414, 141 8 switch means which initiates or terminates the desired timing cycle.

[ References Cited A plurality of the timing modules of the present UNITED STATES PATENTS invention may be juxtaposed in a modular unit for 2,949,017 8/1960 Swanson zoo/3s D x controlling timing functions in a plurality of Output 3,251,956 5/l966 Rasoretal. 200/168KUX ir uits. The respective modules may be readily 3,308,251 3/1967 Schmaus 200/38 R removed from the unit and are interchangeable in 3,699,278 /1972 Jones et a1. 200/38 R position, Means are provided to prevent any two timing modules from initiating a timing cycle Primary ExaminerJames R. Scott simultaneously. Attorney, Agent, or Firm-George W. Price; John H. Gallagher 17 Claims, 7 Drawing Figures F F 10: I I3; I07 |O D I 9 9 54 I a e e F 7 Z 7 4 7 7 r L 2 6 a 6 24 c 5- 5- l s 1 s 1 I Z':[E 2 w I I Q I 1 54A I 1 3E 50 k S t 60A 60 34A 34B 34A 40A PATENTED MHZU3 IHHIIIlllllllllllllllllllllHlll;

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MULTI-CIRCUIT CYCLE TIMER AND MODULAR CONSTRUCTION The present invention relates to an electromechanical timer for initiating a timing cycle at a predetermined time and for terminating said timing cycle at a predetermined subsequent time. More specifically, this invention relates to a modular construction of an electromechanical timer which is adaptable for controlling timing cycles in a plurality of output circuits.

Heretofore electromechanical timers for controlling multiple circuits have included a plurality of timers permanently mounted in a common frame and permanently coupled to each other. Timers of this type suffer from the disadvantage that extensive down-time periods are required in order to repair faulty parts. Also with multi-circuit timers of this type the respective timers are not separable and interchangeable. Therefore, failure of any one given timer causes failure of the entire multi-circuit timing system.

Timers known heretofore have further suffered from the disadvantage that no means were provided for immediately terminating an initiated timing cycle in response to an instruction that the timing cycle initiated is not needed and, therefore, could cause damage to the circuit or process being controlled.

Multi-circuit timers of the prior art have also failed to provide means for preventing an operator from setting the respective timing cycles for simultaneous initiation, which may cause an overload on the system being controlled and an accompanying power failure.

Accordingly, it is an object of the present invention to provide a timing module construction which is adaptable for use in a modular unit for controlling a plurality of output circuits in a predetermined sequence.

It is another object of the present invention to provide a timing module construction wherein each individual timing module is interchangeable with the other and may be easily snapped into place at any desired position within a modular unit.

It is a further object of the present invention to provide a timing module including means for terminating an initiated timing cycle in response to a signal indicating that said timing cycle is not needed.

It is still a further object of the present invention to provide means in a multi-circuit timer control for preventing the simultaneous energization of two or more circuits.

The objects of the present invention are accomplished by providing a plurality of timing modules each module including in combination: a rotary 24 hour timing dial; a rotary two hour timing dial; drive shaft means coupled to said two hour dial for rotating the same; reduction gear train means for coupling said 2 hour dial to said 24 hour dial; actuator means selectively disposed on each of said dials for initiating and terminating a timing cycle; a spring biased pivot lever having cam surfaces thereon for engaging said actuator means at selected time intervals; switch means adapted for engagement with said pivot lever means in response to actuation thereof by said actuator means, said switch initiating or terminating a timing cycle; and means adapted for engagement with said pivot lever for terminating said timing cycle in response to an external control signal.

The use of a 24 hour timing dial and a two-hour timing dial are offered only by way of example as a preferred embodiment. It should be understood that other dial speeds and ratios may be used without departing from the spirit and scope of the present invention.

Each of said timing modules includes a support plate which may be removably snapped into place in a modular support frame. The respective modules are disposed side by side in said support frame and the drive shafts of the respective modules are releasably coupled together. The timing modules are interchangeable so that when one inoperative module is removed for repair and a replacement is not immediately available, an adjacent module may be temporarily moved over to fill the void without interrupting the drive chain.

Means are provided for preventing the programming of the multiple module unit so that only one timing module will initiate a timing cycle at any given time. This prevents the occurrence of an overload in the circuits being controlled.

The timer of the present invention is provided with two drive means. Both drive means are identical and in a preferred embodiment comprise synchronous electric motors disposed on opposite sides of the multiple timer module frame. The motors may be energized simultaneously to drive the timer modules and, if one motor should fail, the other motor will continue to drive the timer modules.

The timing modules described herein are disclosed for use as a control means for initiating a defrost cycle in a freezer or bank of freezers at a predetermined time and means for terminating said defrost cycle at the end of a predetermined period. Although the use of the time module of the present invention for controlling a defrost cycle of a freezer is a preferred use, it should be understood that the timer disclosed herein may be used for other purposes without departing from the spirit and scope of the present invention.

The objects of the invention will become more fully apparent by reference to the following description of the drawings wherein like numerals refer to like parts and wherein:

FIG. 1 is a side elevational view of the timing module of the present invention illustrating the pivot lever in the up position just prior to actuation thereof;

FIG. 2 is a side elevational view of the timing module of FIG. 1 with the pivot lever in the down position just prior to deactivation thereof;

FIG. 3 is a partial view of the timing module of FIG. 1 illustrating the ready position immediately preceeding the activation of the pivot lever;

FIG. 4 is a top plan view illustrating the details of the 2 and 24 hour timing dials of the present invention;

FIG. 5 is a side plan view illustrating further details of the dials of FIG. 4;

FIG. 6 is a partial sectional view of FIG. 1 illustrating the solenoid of the present invention; and

FIG. 7 illustrates a system including a plurality of juxtaposed timing modules of the present invention and a mounting frame therefor. 7

Referring in detail to the timing module of FIGS. 1 to 6 there is shown a timing module generally indicated 10 including a main support plate 26. Support plate 26 is provided with notches 26A, 26B, 26C for receiving module support bars 40A, 40B, and 40C, respectively, of a support frame to be more fully described hereinafter with respect to FIG. 7. A spring biased lever 28 is pivotally mounted on support plate 26 and is provided with a notch 28A for receiving support bar 40A and latching plate 26 thereto. Lever 28 is spring biased toward the position shown so that when module is placed on the respective support bars, bar 40A will snap into the opening defined by notches 26A and 28A and will be retained therein by spring biased lever 28.

The operative components of the timing module 10 generally include a 2 hour timing dial 12 mounted on a main drive shaft 34 journaled in plate 26, a 24 hour timing dial 14 mounted on shaft 14B joumaled in plate 26, a micro-switch 20 for initiating and terminating a defrost cycle, and a spring biased pivot lever 16 having cam surfaces thereon for constraining lever 16 to actuate microswitch 20 in response to the engagement of the cam surfaces with actuator means disposed on the respective timing dials.

Timing dials 12 and 14 are coupled together by a reduction gear train including: pinion gear 36 affixed to drive shaft 34', a first reduction gear 30 coupled to pinion gear 36 and having a pinion gear 30A affixed thereto; a second reduction gear 32 coupled to pinion gear 30A; and pinion gear 38 affixed to shaft 148 of 24 hour timing dial 14. A suitable motor means 52 is coupled to drive shaft 34 and energization of motor means 52 facilitates the simultaneous rotation of both two hour dial 12 and 24 hour dial 14. The reduction gear train is so designed that 2 hour dial 12 makes 12 revolutions for each revolution of 24 hour dial 14.

24 hour dial 14 is provided with slots 14A for selectively receiving substantially U-shaped loading actuator means 24. For reasons that will become more fully apparent hereinafter with reference to FIG. 7, slots 14A may be spaced at positions corresponding to two hour intervals e.g., every other hour or every other half hour. Of course slots 14A can be spaced at any other selected intervals. For example, slots 14A could be spaced at minute intervals for some applications. U-shaped actuator means 24 may be selectively inserted into any desired slot or slots 14A. The operation of loading actuator 24 will be described hereinafter.

Two hour dial 12 mounted on drive shaft 34 includes a defrost-on actuating arm 48 and a defrost-off actuating arm 42. Arms 48 and 42 are provided with actuating pins 48A and 42A, respectively, for engaging cam surfaces 16E and 16D of pivot lever 16 in a manner to be more fully described hereinafter.

As shown most clearly in FIG. 5 defrost-on actuating arm 48 is pivotally mounted about a pin 48C on the surface of dial 12 for movement in slot 46 defining a sector of the surface of circular dial 12. A torsion spring 48B is provided on pin 48C and has a linear portion which extends into abutment with a post 50. The arrangement of spring 488 on pin 48C is such that arm 48 is normally biased against post 50 but when placed under stress, arm 48 will move across slot 46 and engage boss 46A. With arm 48 held against boss 46A actuating pin 48A is rigidly supported for engagement with cam surfacel6E of pivot lever 16. As dial 12 rotates in clockwise direction pin 48A will clear cam surface 16E and snap back against post 50. This snap action of arm 48 prevents pin 48A from hanging up on cam surface 165 in the event that solenoid 22 is actuated to pull foot 22A thereof down against ledge 160 on pivot lever 16 in response to a command signal which indicates that no defrost cycle is necessary.

As shown most clearly in FIG. 5 defrost-off actuating arm 42 is mounted for rotation on shaft 34 with respect to the surface of dial 12. Dial 12 is provided with an annular ring of grooves 44 spaced at one minute increments. Arm 42 has a spring detent portion 42B formed therein which may be selectively snapped into any selected groove 44 by rotating arm 42 about shaft 34. By these means substantially any defrost time period may be selected in the range between zero and 2 hours. In actual practice the range is 6 to 106 minutes due to mechanical limitations on either end of dial 12.

Actuating arm 42 is further provided with an actuating pin 42A which is operatively associated with pivot lever 16 to engage cam surface 16E, as dial 12 is rotated clockwise to constrain lever 16 out of engagement with micro-switch 20 to thereby terminate the defrost cycle.

Pivot lever 16 is mounted for rotation on a pivot pin 16F, which is joumaled in support plate 26. A hole 26D is provided in plate 26 and is operatively associated with a pin 16H which extends from lever 16 into hole 26D to limit the range of rotation of lever 16 about pivot pin 16F. Stated another way the edges of hole 26D function as stop means for lever 16 as it is rotated in either direction. Lever 16 is provided at the bottom thereof with a shoulder portion 16C which rests in a groove in an over center C-spring 18. C-spring 18 is so disposed that it will snap over center as lever 16 is rotated in a clockwise direction to hold end portion 16B of lever 16 in engagement with actuator buttons 20A of micro-switch 20.

Lever 16 is provided with a plurality of cam surfaces 16A, 16D and 16E which are adapted to engage actuator means on dials 12 and 14. Cam surface 16A is adapted to engage actuators 24 as dial 14 is rotated in a counterclockwise direction. The engagement of cam surface 16A with actuators 24 constrains lever 16 to rotate clockwise to a ready position, as shown in FIG. 3, which flexes C-spring 18 to approximately the center position thereof. Cam surface 16E is adapted to engage actuating pin 48A as dial 12 is rotated clockwise, which flexes C-spring 18 over center and pivots lever 16 in a clockwise direction to thereby move end portion 168 of lever 16 into engagement with buttons 20A of microswitch 20. Cam surface 16D is adapted to engage actuating pin 42A as dial 12 rotates in a clockwise direction. The engagement of pin 42A with cam surface 16D constrains lever 16 to rotate counterclockwise, whereby C-spring 18 snaps back over center and 16B rises from engagement with buttons 20A of microswitch 20.

Referring to FIGS. 1, 2 and 6 a solenoid 22 is provided and has a foot 22A which engages the top of a ledge 166 on the back edge of lever 16. Solenoid 22 is connected to a high limit temperature sensor through cables 22C. When a temperature is sensed in a freezer which indicates that the defrost cycle is no longer necessary or a defrost cycle is not needed, solenoid 22 is actuated to pull foot 22A downwardly on ledge 166. Therefore, pivot lever 16 is rotated counterclockwise to open microswitch 20. Since the power to solenoid 22 is supplied through switch 20, solenoid 22 is deenergized as soon as switch 20 opens. As stated above with respect to the description of actuating arm 48, spring 48B causes pin 48A to swing clear of cam surface 16E thereby preventing pin 48A from catching on surface 16E. This prevents solenoid 22 from being subjected to a load which could cause it to burn out and prevents lever 16 from remaining in position against buttons A of micro-switch 20.

Referring to FIG. 4 there is shown a top plan view of dials 12 and 14 illustrating calibration marks and indicia thereon. Dial 12 is provided with marks and indicia comprising a scale 12A thereon the increments of which correspond to settings of the defrost cycle from 6 to 106 minutes. Arm 42 has a V-shaped notch 42C therein to facilitate reading of the indicia corresponding to each selected setting. Dial 14 is provided with two scales 14C and 14D. Scale 14C is provided adjacent notches 14A to designate the time of day on a twenty-four hour clock to which each notch 14A corresponds. Scale 14D is provided for synchronizing the operation of the timing module with the actual time of day at which each selected timing cycle begins. Dial 14 is synchronized with the actual time of day by aligning the appropriate calibration mark thereon with a reference mark (not shown) along the top edge of plate 26. The corresponding calibration marks on scales 14C and 14D are approximately 210 out of phase to allow for the distance between the top of dial l4 and the portion of dial 14 adjacent cam surface 16A.

Referring in detail to FIG. 7 there is shown a modular system including a plurality of timing modules 10 mounted in a commonsupport frame 54 including side plates 54A and 548 connected together by a plurality of transverse support bars 40A, 40B, and 40C.

A drive motor 52 is secured to the outside of a vertical plate 62 by screws of any other suitable means and is connected to a main drive shaft 56 journaled in plate 62. A gear train 58 is coupled to drive shaft 56 and is housed in a space provided between side plate 54A and vertical plate 62. Gear train 58 has a stub 60 journaled in plate 54A and is provided with a slot 60A therein for receiving a stud 34A on the drive shaft'34 of a first timing module 10.. Motor 52 may be any suitable type of electric synchronous motor.

An auxiliary motor 53 may be mounted on plate 54B and may be energized simultaneously with motor 52 to drive the timing modules 10. Therefore, if either motor 52 or 53 should fail, the other motor will continue to drive timing modules 10 without interruption. In the alternative, motor 52 only could be initially energized and control means could be provided for energizing the motor 53 upon failure of motor 52.

As illustrated in FIG. 7 a plurality of timing modules 10 are disposed side by side in support frame 54 on support bars 40A, 40B and 40C. The drive shafts 34 of each respective timing module 10 are coupled together by the respective stubs 34A and slots 348. The modular construction of FIG. 7 has the advantage that if one module must be removed for repair and no replacement is immediately available, then the modules can be shifted to fill the void without substantially interrupting the timing cycles of the other modules.

In a preferred embodiment the spaced slots 14A of 24 hour timing dial 14 of the adjacent timing modules are staggered so that no two timing modules can be set to trigger a defrost cycle at the same time. As shown in FIG. 7 from left to right, four timing modules are illustrated having slots provided at even hours, odd half hours, odd hours, and even half hours. The timing modules illustrated. in FIG. 7 have U-shaped operators 24 inserted therein to facilitate the initiation of defrost cycles at 4:30 AM, 5:00 AM, 5:30 AM, and 6:00 AM, as viewed from right to left.

The purpose for staggering the slots 14A, as shown in FIG. 7, is to prevent more than one defrost heater from turning on at any given time. If more than one heater could possibly turn on at a given time a fuse could blow out or a circuit breaker might be tripped, causing a power failure to the freezers and resulting in the spoiling of frozen foods disposed in the freezers. In a large supermarket this could be a very costly accident. With the timing module system of FIG. 7 it is impossible for an operator to accidently set any two timing modules for the same defrost time, since no two timing modules are provided with spaced slots 14A at the same time settings. Therefore, the possibility of a power failure caused by more than one defrostheater turning on at a given time is virtually eliminated.

The timing dials may of course be calibrated in smaller or larger increments and the slots 14A staggered in other relationships without departing from the spirit and scope of this invention. It should also be understood that although four timing modules are illustrated in FIG. 7, any number of timing modules may be used commensurate with the number of freezers which need to be controlled.

For example, the support frames 54 of FIG. 7 could be constructed to hold four to eight individual timing modules and as many as three to eight frames 54 could be ganged together for controlling a plurality of freezers in a large supermarket. In this type of application it may be possible with slots staggered at half hour intervals for more than one timer to turn on simultaneously. However, the number of timing cycles which may be simultaneously initiated isv kept to a minimum. This can be minimized even further by staggering spaced slots 14A at smaller intervals, such as fifteen minute intervals or any other intervals which will give the desired result for the particular number of load devices being controlled.

The timing modules 10 may easily be inserted into support frame 54 by sliding slot 26C of plate 26 onto support bar 40C and pivoting plate 26 until slot 26B receives support bar 403 and spring biased lever 28 is snapped into place around support bar 40A. Modules 10 may be removed by lifting lever 28 to the position shown in dotted lines in FIGS. 1 and 2 and by pivoting support plate 26 in the opposite direction. This modular construction enables an operator to quickly replace or add a timing module to the system in a minimum amount of time with minimum effort.

DESCRIPTION OF OPERATION The time of day at which a defrost cycle is to begin is chosen by inserting one or more U-shaped operators 24 into selected slots 14A in 24 hour timing dial l4. Timing dial 14 is synchronized with the actual time of day by aligning scale 14D with a vertical reference mark at the top of dial 14. The period or duration of the defrost cycle is then chosen by positioning defrost-off actuating arm 42 at a selected position on 2 hour dial 12. Any defrost period within the 2 hour range may be selected.

A timing cycle then begins by energizing drive motor 52 which causes drive shaft 34 coupled to 2 hour timing dial 12 to rotate in a clockwise direction. The rotary force of timing dial 12 is transferred to 24 hour timing dial 14 by way of the reduction gear train including gears 36, 30, 30A, 32, 38 and causes timing dial 14 to rotate in a counterclockwise direction. Dial 14 rotates at 1/12 the speed of dial l2. Stated another way dial 12 makes one complete revolution for every 2 hours of rotation on 24 hour dial 14.

As timing dial 14 rotates operator 24 will come into contact with cam surface 16A of pivot lever 16, as shown in FIG. 3. This position may be designated the ready position, because as operator 24 pushes against cam surface 16A, lever 16 begins to pivot in a clockwise direction until C-spring 18 is displaced approximately to the center position thereof where it is ready to be pushed over center by actuating pin 48A. At substantially the same time actuating pin 48A of spring biased pivot arm 48 comes into contact with cam surface 16E on bottom surface of the tab extending from the rear of pivot lever 16.

As dial l2 continues to rotate arm 48 traverses slot 46 in the surface of dial 12 until it rigidly abuts boss 46A, as shown in FIG. 1. When this occurs pin 48A pulls upwardly on cam surface 16E causing spring 18 to snap over center, thereby rotating lever 16 clockwise against push buttons 20A of microswitch 20 as illustrated in FIG. 2. Micro-switch 20 may be connected in circuit with a defrost heater or relay and the actuation thereof initiates a defrost cycle.

As spring 18 snaps over center and pivot lever 16 moves into engagement with micro-switch 20, spring biased arm 48 snaps clear of pivot lever 16 to a position against post 50. Solenoid 22 is connected to a sensing means which determines if a defrost cycle is necessary. Such a sensing means could be located in the freezer being controlled. If the sensing means instructs solenoid 20 that no defrost cycle is necessary, solenoid 20 will be actuated pulling foot 22A against ledge 16G and thereby pivoting lever 16 out of engagement with micro-switch 20. Thus the defrost cycle will immediately cease. Since arm 48 and actuating pin 48A thereon have snapped clear of lever 16, there is virtually no danger of pivot lever 16 hanging up from the opposite pulling actions on lever 16 of pin 48A and foot 22A.

If on the other hand the sensing means instructs solenoid 22 that a defrost cycle is necessary, solenoid 22 will not be actuated and lever 16 will remain in the position shown in FIG. 2 until actuating pin 42A on defrost-off actuating arm 42 rotates into engagement with the upper surface 16D of the tab extending from the rear of lever 16. As pin 42A engages surface 16D it constrains lever 16 to rotate counter clockwise, thereby lifting lever 16 from engagement with switch 20 and terminating the defrost cycle. The timing dials l2 and 14 continue to rotate until the next cycle is initiated in a like manner.

If it is desired to control the defrost cycles of a plurality of freezers such as in a supermarket or warehouse, a plurality of timing modules are provided in a common support frame 54, as shown in FIG. 7, and the respective micro-switches and solenoids are connected to separate defrost circuits. All of the timing modules are driven by the common drive means 52.

In programming a multi-circuit defrost timer of the type shown in FIG. 7 it is important to assure that only one defrost cycle is initiated at any given time. Therefore, as stated with respect to the description of FIG. 7, the slots 14A of the adjacent timing modules 10 are staggered to prevent an erroneous setting of the mod ules by an operator. With the slots provided as shown in FIG. 7, it is impossible to set any two timing modules for the initiation of a defrost cycle at the same time.

Referring to the operation of FIG. 7 an operator may select the defrost cycles for the respective modules and freezers being controlled by selectively inserting operators 24 into slots 14A on 24 hour timing dials 14. The duration of each defrost cycle is then set by positioning arm 42 and the module is synchronized with the actual time of day by aligning 24 hour scale 14D with a reference mark at the top of dial 14. Since different types of foods in the respective freezers may require different defrost cycles to prevent damage to the foods, the arms 42 of the respective timing modules may be set at selected positions by referring to an empirical chart indicating the types of food present in the respective freezers. As drive shaft 56 rotates each respective module goes through a timing cycle as described above. As shown in FIG. 7, defrost cycles will be initiated at 4:30 AM, 5:00 AM, 5:30 AM and 6:00 AM as viewed from right to left in FIG. 7.

The invention described'herein may be modified as would occur to one of ordinary skill in the art without departing from the spirit and scope of this invention.

What is claimed:

1. A timer module for generating a timing cycle at a selected time for a selected period comprising:

a. first timing dial means disposed for rotation on a first axis and having actuator means selectively positioned thereon for initiating said timing cycle at a selected time;

b. second timing dial means disposed for rotation on a second axis spaced from said first axis and havinng first and second spaced actuator means thereon, said actuator means being spaced in accordance with the selected period of the timing cycle;

0. gear means for coupling said first and second timing dials together;

d. drive means for synchronously driving said first and second dials at predetermined relative speeds;

e. switch means having a first position for initiating said timing cycle and a second position for terminating said timing cycle; and

pivot lever means pivotally mounted for rotation about a third axis, said lever having cam surfaces thereon disposed for selective engagement with the respective actuator means of said first and second dials in a predetermined sequence for pivoting said lever into or out of engagement with said switch means to selectively move said switch means into said first or second positions, respectively, to control said timing cycle.

2. The timer of claim 1, wherein over center spring means are provided for normally biasing said pivot lever out of engagement with said switch means.

3. The timer of claim 2, wherein the cam surfaces of said pivot lever means include:

a. a first cam surface for engaging said actuator means on said first timing dial, as said dial rotates, which pivots said lever and said over center spring to a ready position which substantially coincides with the center position of said over center spring;

b. a second cam surface for engaging said first actuator means on said second dial when said lever is in said ready position, and pivoting said lever to snap said spring over center, whereby said lever is pivoted into engagement with said switch means to initiate said timing cycle; and

c. a third cam surface for engaging the second actuator means of said second timing dial for pivoting said lever means out of engagement with said switch means to thereby terminate said timing cycle.

4. The timer of claim 3, wherein said first actuator means of said second dial is spring biased to swing clear of said second cam surface immediately following the engagement thereof.

5. The timer of claim 3, wherein the relative predetermined speeds of said first and second dials are such that said first timing dial makes one revolution every 24 hours and said second timing dial makes one revolution every 2 hours.

6. The timer of claim 3, wherein said first timing dial includes slots in the face thereof and said actuator means of said first dial are selectively inserted in said slots.

7. The timer of claim 6, wherein said slots in said first dial are spaced at time intervals on said first dial corresponding to the time of one revolution of said second dial and each slot aligns with said first cam surface simultaneously with the alignment of the first actuating means of the second dial with said second cam surface.

8. The timer of claim 6, wherein said first timing dial includes a first time scale for synchronizing the timer with the time of day and a second time scale for selecting the time of day at which said timing cycle is initiated.

9. The timer of claim 1, wherein means are provided for pulling said lever out of engagement with said switch means during said timing cycle in response to a command signal from a device being controlled.

10. The timer of claim 1, wherein the space between said first and second actuator means on said second dial is selectively adjustable to control the period of said, timing cycle.

11. The timer of claim 1, wherein said second timing dial is mounted on a rotary shaft having a stub means at one end thereof for connection with a slot in the end of a drive shaft of said drive means and a slot means at the other end thereof for receiving the stub of the rotary shaft of another like timer module, whereby a plurality of said timer modules may be coupled together and driven by the same drive shaft.

12. The timer of claim 1 further including a support plate on which the components of said module are disposed, said plate having slots therein for receiving support bars of a modular support frame structure, at least one of said slots having a spring biased latch associated therewith for latching said plate to at least one of said support bars.

13. The invention of claim 12, wherein said latch means comprises a spring biased pivot lever having a slot therein for receiving said at least one support bar.

14. In a multiple time control device, a plurality of separate timer modules disposed side by side, a plurality of rotary operator means for controlling respective timing cycles, one for each of said timer modules, said operator means being arranged side by side, means including gear means for driving said operator means, and motor means for driving said gear means, the improvement comprising:

a. support frame means including a plurality of transverse support bars extending between a pair of side support plates;

b. support plate means for supporting each of said timer modules,

0. a plurality of open slot means on the periphery of each support plate means adapted to releasably engage respective support bars of the support frame upon transverse insertion of a support plate in said frame, whereby said plates are releasably supported on said frame,

15. The invention of claim 14, wherein at least one of said slot means includes a spring biased latch means associated therewith for latching at least one of said support bars in said at least one slot means.

16. The invention of claim 15, wherein said latch means comprises a spring biased pivot lever having a slot therein for receiving said at least one support bar.

17. The invention claimed in claim 16 wherein each operator means includes a respective drive shaft, the drive shafts of the side by side operator means being axially aligned,

releasable coupling means on each of the drive shafts for releasably coupling said drive shafts together, whereby said motor means and the means including gear means drives all of said operator means through the coupled drive shafts. 

1. A timer module for generating a timing cycle at a selected time for a selected period comprising: a. first timing dial means disposed for rotation on a first axis and having actuator means selectively positioned thereon for initiating said timing cycle at a selected time; b. second timing dial means disposed for rotation on a second axis spaced from said first axis and havinng first and second spaced actuator means thereon, said actuator means being spaced in Accordance with the selected period of the timing cycle; c. gear means for coupling said first and second timing dials together; d. drive means for synchronously driving said first and second dials at predetermined relative speeds; e. switch means having a first position for initiating said timing cycle and a second position for terminating said timing cycle; and f. pivot lever means pivotally mounted for rotation about a third axis, said lever having cam surfaces thereon disposed for selective engagement with the respective actuator means of said first and second dials in a predetermined sequence for pivoting said lever into or out of engagement with said switch means to selectively move said switch means into said first or second positions, respectively, to control said timing cycle.
 2. The timer of claim 1, wherein over center spring means are provided for normally biasing said pivot lever out of engagement with said switch means.
 3. The timer of claim 2, wherein the cam surfaces of said pivot lever means include: a. a first cam surface for engaging said actuator means on said first timing dial, as said dial rotates, which pivots said lever and said over center spring to a ready position which substantially coincides with the center position of said over center spring; b. a second cam surface for engaging said first actuator means on said second dial when said lever is in said ready position, and pivoting said lever to snap said spring over center, whereby said lever is pivoted into engagement with said switch means to initiate said timing cycle; and c. a third cam surface for engaging the second actuator means of said second timing dial for pivoting said lever means out of engagement with said switch means to thereby terminate said timing cycle.
 4. The timer of claim 3, wherein said first actuator means of said second dial is spring biased to swing clear of said second cam surface immediately following the engagement thereof.
 5. The timer of claim 3, wherein the relative predetermined speeds of said first and second dials are such that said first timing dial makes one revolution every 24 hours and said second timing dial makes one revolution every 2 hours.
 6. The timer of claim 3, wherein said first timing dial includes slots in the face thereof and said actuator means of said first dial are selectively inserted in said slots.
 7. The timer of claim 6, wherein said slots in said first dial are spaced at time intervals on said first dial corresponding to the time of one revolution of said second dial and each slot aligns with said first cam surface simultaneously with the alignment of the first actuating means of the second dial with said second cam surface.
 8. The timer of claim 6, wherein said first timing dial includes a first time scale for synchronizing the timer with the time of day and a second time scale for selecting the time of day at which said timing cycle is initiated.
 9. The timer of claim 1, wherein means are provided for pulling said lever out of engagement with said switch means during said timing cycle in response to a command signal from a device being controlled.
 10. The timer of claim 1, wherein the space between said first and second actuator means on said second dial is selectively adjustable to control the period of said, timing cycle.
 11. The timer of claim 1, wherein said second timing dial is mounted on a rotary shaft having a stub means at one end thereof for connection with a slot in the end of a drive shaft of said drive means and a slot means at the other end thereof for receiving the stub of the rotary shaft of another like timer module, whereby a plurality of said timer modules may be coupled together and driven by the same drive shaft.
 12. The timer of claim 1 further including a support plate on which the components of said module are disposed, said plate having slots therein for receiving support bars of a modular support frame structure, at least one Of said slots having a spring biased latch associated therewith for latching said plate to at least one of said support bars.
 13. The invention of claim 12, wherein said latch means comprises a spring biased pivot lever having a slot therein for receiving said at least one support bar.
 14. In a multiple time control device, a plurality of separate timer modules disposed side by side, a plurality of rotary operator means for controlling respective timing cycles, one for each of said timer modules, said operator means being arranged side by side, means including gear means for driving said operator means, and motor means for driving said gear means, the improvement comprising: a. support frame means including a plurality of transverse support bars extending between a pair of side support plates; b. support plate means for supporting each of said timer modules, c. a plurality of open slot means on the periphery of each support plate means adapted to releasably engage respective support bars of the support frame upon transverse insertion of a support plate in said frame, whereby said plates are releasably supported on said frame.
 15. The invention of claim 14, wherein at least one of said slot means includes a spring biased latch means associated therewith for latching at least one of said support bars in said at least one slot means.
 16. The invention of claim 15, wherein said latch means comprises a spring biased pivot lever having a slot therein for receiving said at least one support bar.
 17. The invention claimed in claim 16 wherein each operator means includes a respective drive shaft, the drive shafts of the side by side operator means being axially aligned, releasable coupling means on each of the drive shafts for releasably coupling said drive shafts together, whereby said motor means and the means including gear means drives all of said operator means through the coupled drive shafts. 